Heat at the right time, from a controller built on retired smartphones

Challenge

Choosing when one heats impacts what one pays

A home with a heat pump and solar panels already has most of what it needs to heat itself at a lower cost. What it lacks is timing. The heat pump heats when the thermostat asks, and that moment is not always the one when the sun is on the roof or when electricity is at its cheapest. Power the household could have used goes back to the grid, and heat that could have been made in the afternoon gets made in the evening.

Supplying that timing means placing a small computer next to the heat pump and asking a great deal of it. It has to follow the house, the solar production and the price of electricity at the same time. It has to stay reachable over the internet for as long as a heating system lasts, which is counted in years rather than seasons. It has to act on heat pumps of many different brands. And it has to keep doing all of that in a utility room, unattended, inside a product a household buys once and then stops thinking about.

Solution

Controlling heat production around what each house needs

Destore Sense is built on a circular compute module from Citronics. The module is a computer and its connections, recovered from a smartphone that had been withdrawn from use, then tested and qualified so that a product can be designed around it. A phone leaving service still holds a capable computer together with mobile and wireless connections, which is close to the list of what a control unit in a house has to provide, and the recovery and the preparation take place in Europe.

Around that module Destore built what makes the unit its own. Fitted beside the heat pump, the unit measures the water temperature going into and out of the pump, reads the home's electricity meter, and picks up room temperature and humidity from a small wireless sensor placed in the living space. It reaches the internet through the home network, or over a mobile connection where there is none. To act, it uses the control inputs that heat pump manufacturers already provide, which is what lets a single unit work with many brands rather than one.

The unit does not decide alone. What has to be decided in the house is decided in the house, close to the equipment and without waiting for an answer from a server, while the platform behind it holds the wider view and Destore can reach each unit remotely to follow it and to update it.

Benefits

Fast to develop, built to last a product lifetime

Development time went where it counted. The computing part arrived tested and ready to build on, so the work in front of Destore was the work only Destore could do: the control logic and the heat storage. It also arrived with a development platform built on the standard, open tools embedded engineers already use, so the software for Sense could be written the way the team was used to writing software rather than learned first.

That platform keeps working once the product leaves the workshop. A heating system stays in a house for years, and units in the field can be monitored, updated and security patched remotely across that whole life, which is what lets control logic keep improving on equipment that is already installed. Documentation and support come with it, as does help with the certification work a product of this kind has to pass.

The computing heart of the product is also sourced and prepared in Europe, from equipment already on the continent, which keeps Destore close to the parts its product depends on.